Fact of the week
Our disappearing biodiversity
The passenger pigeon, the woolly mammoth and the Tasmanian tiger – what do they all have in common? They are extinct. But how many animals have died out? And how many more will? Global Ideas takes a look.
Ten thousand every year, 150 a day, three every hour – estimates on the number of species that become extinct in a given time period, vary wildly. But what everyone does agree on, is that they are being lost at a higher rate than would be the case if we humans were out of the picture. Anything, say scientists, between 1,000 and 10,000 times higher. And it's our fault.
From the forests we clear to make way for agricultural land to the resources we overexploit in an effort to satisfy our appetite for meat and fish, the way we lead our lives is stripping our fellow species of habitat and food. In short, it's causing some species to die out.
To date, some 1.9 million species have been identified globally, although the International Union for Conservation of Nature (IUCN) estimates there could be between 13 and 14 million in existence. Other studies have put the figure at approximately 8.7 million, basing the estimate on the taxonomic rank – or classification – of species and their number.
Without knowing exactly how many species of flora and fauna exist in the world, it's almost impossible to know how many are disappearing. But over the last 500 years, 869 have been recorded as having gone extinct as a result of human activity. And while to some that might not sound like a lot, each species plays an important role in its ecosystem and the loss of one can have a detrimental effect on others.
Tasmanian tigers lived at a zoo in Washington DC between 1902 and 1905
Species at risk
We also know that animal and plant life are increasingly at risk of dying out. There are 79,000 species on the IUCN's Red List, which categorizes animals based on the level of threat – from least concern to vulnerable, critically endangered and extinct. The number of threatened species has increased from 5,205 in 1996 to its current 8,462.
Scientists have described this trend as a"biological annihilation" . They say we are going through a "sixth mass extinction”, following on from past extinctions caused by climate change, an ice age and the impact of a giant asteroid, which wiped out the dinosaurs.
Pandas are back from the brink
But there's hope. Global conservation efforts have seen the rejuvenation of species previously on the brink of extinction. Until last year, the giant panda was classified as "endangered” on the IUCN's Red List, but numbers have been increasing. Between 1985 and 1988, around 1,200 were recorded in the wild, and now the population is thought to be higher than 1,800, which has led to it being reclassified as "vulnerable”.
Providing incentives to protect endangered species and limiting the destruction of habitats are just some of the measures conservationists believe will slow down the rate of extinction, and thereby give the animal and plant species that exist today the chance to survive.